1. Field of the Invention
The present invention relates to a method of rolling of a bar-shaped stock, e.g., a bar steel or wire to predetermined end height and end width measured transverse to the end height by application of rolling forces, and to a rolling mill train for implementing the method and including a plurality of arranged one after another active rolling mill stands having adjustable roll nips and forming rolling mill stand pairs.
2. Description of the Prior Art
The rolling mill trains of the type described above are generally known. The rolling mill stands are alternatively formed as horizontal rolling mill stands and vertical rolling mill stands, with the last rolling mill stand defining the end profile, e.g., round, square or hexagonal profile.
In the prior art, the roll nips of the rolling mill stands are adjusted with electric or hydraulic motors. However, the adjustment of the roll nip can be mostly effected in the unloaded condition only. The adjustment of the roll nip under a load is not possible. It is possible to change the rotational speed of the rolling mill stands during their operation. Other interventions, e.g., a correction of roll nips, is not possible.
A co-pending U.S. application Ser. No. 09/348,745 discloses a rolling mill train for rolling a bar-shaped stock including a plurality of active rolling mill stands through which a rolled stock passes one after another and the roll nips of which are adjusted with respective hydraulic cylinder units. There are further provided control units for controlling the operation of the respective hydraulic cylinder units so that a fraction of the rolling force-caused spring-offs of the rolling mill stands is compensated.
An object of the present invention is to provide a method of and a rolling mill train for rolling a bar-shaped stock with which the roll nips can be adjusted under load and the rolling characteristics of the rolling mill stands are adaptable to respective rolled stock.